Relief device for lubricating apparatus



June 2o, 1939. L, C, ROTTER "2,162,898

` RELIEF DEVICE FOR LUBRICATING APPARATUS Filed Jan. .17, 1938 FIG. l.

III... IIIN" Y Patented June 20, 1939 UNITED` STATES 2,162,898 RELIEFnaviga Fon. LUBBICATING Lutwin- C. Rotter, Maplewood,

Lincoln Engineering Company, a corporation of Missouri PARATUS Mo.,assgnor St. Louis, Mo.,

Application January 17, 193s, serial No. 185,315 7 claims. -(cl. 277-61)This invention relates to lubricating apparatus, and more specificallyto relief valves for use in apparatus such as described in my patentapplication, Serial No. 137,555,' led April 17, 1937,

now Patent No. 2,141,022, granted May 27, 1938,

for Lubricating apparatus. The present application is acontinuation-in-part of the 4former application. A

Among the several objects of the invention 10 may be noted the provisionof a relief valve for use in a lubricating system for forcing lubricantto remotely located bearings in predetermined, ,measured charges; theprovision of a relief valve of this class which Awill open a by-passonly in l5 response to relatively high pressure, but which after saidby-pass has been opened will maintain the opening under relatively lowerpressure; and the provision of a relief valve of the class describedhaving improved mechanical features.

Other objects will be in part obvious and in part pointed outhereinafter.

The invention accordingly comprises the elements and combinations ofelements, features of construction, and arrangements of parts which willbe exemplified in the structures hereinafter adescribed, and the scopeof the application of y whichwill be indicated in the following claims..

In the accompanying drawing in which are shown several of variouspossible embodiments of the invention,

Fig. 1 is a vertical section of a relief valve, indicating apressure-transmitting condition;

Fig. 2 is a. view similar to Fig. 1 in which the valve is in relievingposition; and,

Fig. 3 is a view similar to Fig. l showing an alternative mechanicalform of the invention.

Similar reference characters indicate corresponding parts throughout theseveral views of the drawing. l y

The relief valve herein described is for use in connection with apressure line 3| from a suitable lubricant pump (not shown).4 Theline'3l is intended to deliver lubricant to a distribution line 39. Inthe distributionl line 39 are certain injectors (not shown) whichoperate lunder a. certain pressure to receive -iuid from line 39, andthereafter resist receiving fluid from the distribution line 39, evenwhen the pressure in said line 39 builds up under pumping action. At acertain value of this pressure, .itis intended that the relief valveherein shall open and permit return of lubricant through the return orbypass line 31 to the pump supply. i

It is also intended when the pump stops pump', 55 ing that pressureshall be relieved from the mally presses tribution line 39 down to avalue which is lower than the opening pressure of the relief valve.Thus, the relief valve (numbered generically as 35, herein) is used inconnection with a by-pass 31 back to the container, but the lubricantnor-l mally may pass through a passage such as shown at 33 and to thedistribution line 39.

The relief valve 35 (Figs. 1 and 2) comprises a cylinder 4| in which isa slidable piston 43 having a conical face 45 for seating at a reducedarea on the edge of a relatively small passage 41 located between thepassage 33 and the cylinder 4|. The outlet 38 to the by-pass 31 is.normally covered by said piston 43 but under certain conditions isuncovered. A spring 49 northe piston downwardly, as shown in Fig. 1. Astem 5| which passes through a bearing 53 serves as a tell-tale. Thepassages 41 and the part of cylinder 4| below the piston 43 are referredto in the claims as a first communication.

An auxiliary communication 55 connects the transmission passage 33 withthe Aby-pass 31 and in this communication is a valve 51 which isnormallyspring pressed open toward passage 33. This is done by means ofan opening spring 59.

A relatively'high pressure is requiredin the passage 33 in order to openthe port 41 (forv example, 3000 lbs. per sq. in.). After the port onceopens, a relatively lower pressure will maintain it open (for example,100 lbs. per sq. in.). Thus relief is effected until the pressure dropsto a value far below that which was required initially to open the p ort41.

The valve 51 is set to open at a pressure in passage 33 which is higher(preferably slightly higher) than said lower pressure, so that the valve51 will remain open when the piston valve 45 closesand until a higherpressure is again built up in passage 33 than exists at the time thatthe valve 45 closes. B ut, in any event, this opening pressure of valve51 must be lower than the opening pressure for valve 45 to insureinitial relief through valve 45, (for example, on the above basis, valve51 may remain open at 105 lbs. per sq. in.) Valve passage 55 is referredto in the claims as a second communication.

The operation of the apparatus of Figs. 1 and 2 is as follows:

Before pumping starts, the valve 51 is open, but promptly after pumpinghas started it becomes shut. As above described a considerable unitpressure may be exerted on the small area of the conical valve portion45 which covers the passage 41 before the piston 43 will be raised.Thus, during the first part of the pumping period, and as the pressurebuilds up in the passage 33, the valve portion 45 is shut as is alsovalve 51 (see Fig. 1). This permits the necessary functioning of theapparatus connected with the distribution line 39, as described in myparent application, already identified.

Continued pumping then increases the pre'ssure. The pressure in the port41 of the relief valve 35 finally becomes great enough that the pistoniluid ows back through the by'pass line 31. It will be seen that as soonas the port41 is opened, the enlarged area of the entire cone 45 isexposed to the pressure, so that thereafter a lower pressure serves tohold the piston 43 clear of the port 38. Hence, even though the pumpceases operatinng and the pressure in line 39 drops,(bleeds oi), thepiston 43 will remain up as the lower pressures eventuate. The diametersof piston 43 and of the seat on the port 41 are so calculated thatnormally, before the port 41 shall have been closed, the necessaryfunctions in the apparatus connected to line 39 shall have beenperformed.

The purpose of the auxiliary or second valve 51 is to meet conditionswherein a relatively long line 39 is used which may have a relativelylarge amount ol.' friction therein. Under such conditions, uponcessation of pumping and bleeding of the line 39, the part of the line39 adjacent the relief valve 35 only bleeds off promptly, while thedistant remainder may, due to friction, lag in losing its relativelyhigh pressure. -This may result -in the reclosure of the cone 45 overthe port 41 before the distant apparatuses have been bled of pressure,in which event said distant apparatuses would not operate.

As soon as the port 41 is opened, there isa substantial balance ofpressure on opposite sides of said valve 51,' which then opens. Itremains open, due to balance of pressure, as long as valve 45 is open.At the time the valve 45 reseats, the valve 51 is held open by its ownspring Ato take care of bleeding under vlower pressure conditions thanvalve 45, while open, is adapted to take care of, as under slow pressureloss in a long line with high friction.

By the time that the pump is again started thevalve 45 has closed andremains closed until relatively high pressure conditions arere-established. As these hlgh-pressure conditions are reestablished thevalve 51 again shuts due to excess pressure in passage 33 which isgreater than the pressure of spring 59. Thus while the valve formed bythepiston 43 normally serves to bleed oi the pressure, the valve 51serves to bleed it olf under lower pressure conditions, as vwith slowleakage from a long line.

It will be seen that whenever the pressure builds up to force its way'Athrough the port 41, thereafter said port opens up wide, thereby quicklyrelieving the pressure. The relief of this pressure can be detected bythe visual signal at telltale In Fig. 3 is shown a modied form of therelief valve 35' in which like primed numerals designate like parts.'I'he improved features of this form of the invention are primarilystructural. In this form the piston 4 3 traverses a counter-bore 6|which communicates with the passage 38 leading to the by-pass line 31'.'I'he piston 43 is packed against leakage in cylinder 4| by packing 15.Also, the conical valve por- 43 rises to uncover the by-pass, whereupontion 45 of the piston 43' is separate and made as a hardened steelinsert, fitted loosely into a socket 63 within the piston 43. Thisconical insert 45' engages with a hardened seat 65 which is screwed intothe body portion 61.

'I'he body portion 61 forms the base to which is threaded the cylinder4|. Upward movement of the piston 43 is limited by a shoulder 69 in thecylinder 4|'. The lower edge of the'piston 43 is formed as a lip 1|which cooperates slidably with some clearance with a counterbore 13 inthe body 61. The lower edge of the lip 1| passes above the counterbore13 when pressure forces the'rpiston 43' against the shoulder 69.

The length of the shank 8| of the valve insert 45 is long enough thatwhen the vtop of the piston 43'lstrikes the shoulder 69, the shank 8|will still extend part Way into the socket 63. The shank 8| is madeloose enough to permit of selfcentering of the valve 45 against seat 65.If the valve drops down, it will not leave the socket 63 entirely.

The separable conical valve 45 associated with the piston 43 in Fig. 3is the equivalent of the piston 43 with the conical nose 45 shown inFigs. 1 and 2, so far as the functions of the apparatus are concerned.However, the valve 45 of the piston 43 in Fig. 3 has-the statedself-centering structural advantages.

The operation of the form of the invention shown in Fig. 3 is analogousto that related in connection with the forms shown in Figs. 1 and 2,

with the exception of the fact that Ithe closer lit between lip 1| andthe counterbore 13 eiiects more throttling than the looser iit betweenthe cylinder 4|' and piston 43 in Figs. 1 and 2. Thus, there is atendency to delay the period of pressure reduction. This results inbetter assurance of a longer line being properly bled oi without aid ofthe auxiliary valve 51'. In other words, the closing of valve 45 (Fig.3) is delayed more than that of valve 45 (Figs. l'and 2).

It will be seen from the above that as the pressure is bled olf fromunder the piston 43', in both forms of theinvention, the relationshipbetween the passage 38', cylinder 4|', and piston 43' is such that thepiston increasingly throttles the outlet 38' as the pressure under thepiston goes down. The effect of this is to slow down the pressurerelease as the pressure goes down, so thatl more time is given to bleedlong lines. This tends to extend the scope of use of the device for longlines, with or without the valve 51. In the Fig. 3 form, the t betweenrecess 13 and lip 1| is of the throttlingv and not of the completelysealing type.

Although there has not been shown in connection with the form of Fig. 3any valve corresponding to valve 51, such a valve may be used.Furthermore, the valve 51 is not always necessary, as with short lineshaving low friction therein. Moreover, a valve such as 51 may be used asa `separate device in connection with a separate relief valve such asdescribed.

Another advantage in the case of the reduced clearance betweencounterbore 13 and the piston 43 (Fig. 3), is that better conditions ofalignment are maintained for the valve 45' and its seat 65. Thus, thelooseness o1" valve 45' in its socket 63 may be at a minimum foreffective self-centering.

It will be seen that in all forms of the invention herein a lock nut 30or 3D' is threaded to the member 53 or 53', as the case may be. Thispermits of locking in position sai-d member 53 (or 53') after adjustmentto any predetermined posi aieases tion. Thus, it is possible to vary thepressure exerted by spring 49 or- 49' and the resulting pressurecondition' in the passage 33 'or 33' `at which the valve 45 or 45' willopen.

In View of the above, it will be seen that the several objects of theinvention are achieved, and other advantageous results attained.

vAs many changes could be made in carrying out the above constructionswithout departing from thescope of the invention, it is intended thatall matter contained in the above description or shown in theaccompanying drawing shall be interpreted as illustrative and not in alimiting sense.

I claim:

1. A relief valve comprising a pressure-transmitting passage, a by-pass,a iirst communication between said passage and said by-pass including arelatively small passage and a reltively large cylinder, a piston ofrelatively large area fitting said cylinder, a relatively small end areaof said piston covering said small passage, a spring biasing said pistonnormally to close said passage, said small end area requiring arelatively high pressure to open said piston, but the relatively largepiston area requiring a relatively small pressure' to maintain opening,a second communication between Asaid transmitting 'passage and saidby-pass, and

valve means normally urged open 'by a spring and adapted to open thesecond communication under pressure in the transmitting passage which isabove the closing pressureof the piston as the rst communication isclosed. 2. A relief valve comprising a pressure-transmitting passage, aby-pass, a iirst communication between said passage and said by-passincluding a relatively small passage and a relatively large cylinder, apressure-receiving means in said cylirider, a relatively small area or"said pressure-receiving means covering said small passage, means biasingsaid'pressure-receiving means normally to close said passage, saidVsmall area requiring a relatively high pressure to open said piston,but the relatively large pressure-receiving means requiring a relativelysmall pressure to maintain the opening, a second communication betweensaid transmitting passage and said by-pass, and valve means ad Vpted toclose the second communication unde the pressure in the transmittingpassage associated with a closed position of the pressure-receivingmeans, but said valve means being normally biased to remain open underpressure:

in the pressure-transmitting passage above the pressure on the pistonasthe iirst communication is being c1osed, the transmitting passage andthe two communications being arranged so that the opposite sides of saidbiased valve means are subjected to substantially balancing pressureswhen the piston permits its associated passage to be open.

3;, A relief valve comprisingl a pressure-transmitting passage, aby-pass, a rst communication between said passage and said by-passincluding a relatively small passage and a rel-atively large cylinder, apiston of lrelatively large area tting said cylinder, a relatively smallend area of said piston covering said small passage, i

a spring biasing said piston normally to close said passage, said smallend area requiring a relatively high pressure to open said piston butthe relatively large piston area requiring a relatively small pressureto maintain opening, a

second communication between said transmitting passage and said by-pass,and valve means normally biased toward open position and adapted toclose the second communication under substantial pressure in thetransmitting passage above the closing pressure of the piston when therst communication is closed and adapted to hold open the secondcommunication when under a pressure in the transmitting passage whichisI the closing pressure of the piston as the rst communication closes,said piston, cylinder and by-pass being so related that the pistonincreasingly throttles the by-.pass as pressure decreases.

4. A relief valve comprising a pressure-transmitting. passage, aby-pass, a rst communication between said passage and said by-passinvcluding a relatively small passage and a relatively large cylinder, apiston o! relatively large area fitting said cylinder, a relativelysmall end area of said piston covering said small passage, a springbiasing said piston normally to close said passage, said small end arearequiring 'a relatively high pressure to open said piston but therelatively large piston area requiring a'relatively small pressure tomaintain opening, a second communication between saidtransmittingpass-age and said by-pass, valve means normally biased toward openposition and adapted to close the second communicationunder substantialpressure in the transmitting passage above the'closing pressure of thepiston when the rst communication is closed and adapted to open thesecond communication when under a pressure in the transmitting passagewhich is the closing pressure of the piston as the iirst communicationcloses, the transmitting passage of the twocommunications being arrangedso that opposite sides of said valve means are subjected to substantialbalancing pressures after the piston opens the first passage, saidpiston, cylinder and by-pass being so'related that the pistonincreasingly throttles the bypass as pressure decreases.

5. A relief valvel comprising a pressure-transmitting passage, aby-pass, a rst communication betyeen said passage and saidby-passincluding a relatively small passage and a relatively large cylinder, apiston of relatively large area fittingV ypressure vto open said piston,but the relatively large piston area requiring a relatively smallpressure to maintain opening, and a second communication between saidtransmitting `passage and said bv-pass, valve means adapted to close thesecond communication under substantial pressure in the transmittingpassage but normally biased to remain open under pressure in thetransmitting passage slightly above the closingr pressure existingv asthe first communication is 6. A relief valve comprising apressure-transl mitting passage, a' by-pass, a iirst communicationbetween said passage and said by-pass, valve means'associated with thefirst communication, said valve vmeans being adapted to hold thecommunication closed up to a relatively high pressure in thetransmitting passage, and to maintain an opening under relatively lowerpressure therein after the communication has once opened attherelatively higher pressure, and to close under still lower pressureconditions, a second communication lbetween said transmitting `passageand said by-pass, and normally biased valve meansl in the second'communication adapted to move against its normalV bias to hold closedthe second' communication under pressuresy in the transmitting passageconstituting a range from a predetermined value up to the pressurerequired initially to open the valve in the first communication, butadapted under` its bias to move to open the second communication underpressure conditions existing in the rst" normallyV biased to a closedposition wherein any pressure diierence up to a predetermined highpressure diilerence may be maintained between the passage and theby-pass without opening the valve, the valve being adapted to open atsaid predetermined high pressure difference and to remain open at apressure diierence between the passage and the by-pass which is -of avalue lower than said high pressure diierence, a second communicationbetween the passage and the bypass, valve means in the secondcommunication normally biased open toward the pressure-transmittingpassage and adapted to open and remain open under a pressure at andbelow said lower pressure diierence. f

LU'I'WIN C. RQTTER.

